The researchers concluded that yoga classes are likely to be a cost-effective treatment for back pain forthe NHS if it managed to maintain the cost below £300 per patient for a cycle of 12 classes.

The patients in the yoga classes took ‘far fewer' days off work than those in the control group, making it more cost-effective for society as a whole.

The report, funded by Arthritis Research UK, said back pain is estimated to cost the NHS £1.37bn and the healthcare sector £2.1bn a year, with 2.6 million people seeking advice from their GP about back pain each year.

Professor David Torgerson, chief investigator professor at the University of York's department of health sciences, said: ‘While yoga has been shown as an effective intervention for treating chronic and low back pain, until now there has been little evidence on its cost-effectiveness. In our study we evaluated a specially designed yoga class package by using individual-level data from a multi-centred randomised controlled trial.

‘On the basis of the 12-month trial, we conclude that 12 weekly group classes of specialised yoga are likely to provide a cost-effective intervention for the treatment of patients with chronic or recurrent low back pain.'